This invention relates to hand tools, and more particularly to a device known as a cutting guide or straight edge guide, for use in connection with a workpiece, to mark or cut in a straight line on the workpiece.
Various forms of cutting guides or straight edge guides are known, and reference is made to U.S. Pat. No. 4,463,644 to Ferdinand et al and U.S. Pat. No. 3,915,045 to Kitzman for examples of such devices. Generally, cutting guides of the type disclosed in the noted patents consist of a pair of rails, each of which has a straight guide edge, with the rails being joined together to form a continuous guide edge having sufficient length to span the length of an eight-foot workpiece, such as a conventional 4' by 8' sheet of plywood or paneling. Other low-cost cutting guides are known, as will be set forth in detail hereafter.
It is an object of the present invention to provide a cutting guide consisting of a pair of guide rails, in which the rails are relatively inexpensive to produce yet provide a reliable guide edge and sufficient strength to maintain the straightness of the cutting guide even after repeated use. It is a further object of the invention to provide a cutting guide in which the guide rails are connected in a simple and efficient manner, with the connection insuring that the vertical guide edges of the rails are aligned with each other by the action of the rails being connected together.
In accordance with the invention, a cutting guide consists of a pair of guide rails, each of which defines a guide wall. The guide rails are adapted for placement in an end-to-end relationship such that outer surfaces of the guide walls cooperate to form a continuous straight guide edge. Each rail defines a channel, including a ramped surface and a stop surface disposed within the channel. A clamp member is adapted for placement within the first and second guide rail channels. The clamp member includes a first portion engageable with the ramped surface of each rail, and a second portion engageable with the stop surface of each rail. A series of engagement members, such as threaded screws, are interconnected with the clamp member, with at least one screw engaging each one of the guide rails. Engagement of the guide rails by the screws results in movement of the clamp member first portion along the ramped surfaces of the rails until engagement of the clamp member second portion with the stop surfaces of the rails. In this manner, the first and second guide rails are securely held together, and the outer surfaces of the first and second guide walls are aligned to form a continuous straight guide edge.
The ramped surface is preferably provided on a lip formed integrally with each guide rail, and the stop surface of each rail is defined by an inwardly facing surface formed by the guide wall, with the ramped surface facing the stop surface. The clamp member consists of a pair of spaced flanges with a web extending therebetween, and the clamp member first and second portions are defined by one of the clamp member flanges. An outer surface of a clamp member flange makes up the clamp member first portion, and the outer end of the clamp member flange makes up the clamp member second portion. With this arrangement, the outer end of the clamp member flange rides along the ramped surface when the screw is turned down in the clamp member to engage the rail, until the outwardly facing surface of the clamp member flange engages the stop surface defined by the inner surface of the guide wall.
The guide rail further includes a support surface defined by a second lip spaced from the first-mentioned lip, and the other of the clamp member flanges is engaged with the support surface. During movement of the outer end of the clamp member flange along the ramped surface, the other clamp member flange rides along the support surface. With this arrangement, engagement of the guide rail stop surface by the outwardly facing surface of the clamp member flange insures that the outer surfaces of the guide wall are in alignment when the guide rails are clamped together by engagement of the guide rails by the clamp member and the screws.
The invention further contemplates a method of assembling a cutting guide, consisting of a pair of guide rails and a connector member, substantially in accordance with the foregoing summary.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.